The design on this cup is called Iona and was "adapted" by Jane Brookshaw. She has obviously no idea of the discipline involved in knotwork. Lines should go under then over and under then over and so on. In effect she has copied a good design badly. Had she slavishly copied a good design properly the result would have been less irritating!
I have roughly and quickly corrected these errors, and you can see the comparison in the image below:
Lines flow under and over as they should do in proper knotwork in the corrected version (not over and over as they do in the top image).
Unfortunately I was given, as a present, another cup with a design "adapted badly" by the same lady. See if you can find the errors in the image below before scrolling down to the solution. You are looking for threads or paths which do not intertwine properly. I.e. they do not go under and over and under and over:
And here are the unknotted "knots":